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Hormesis in Yeast. Cao Tian Qin 4S104 Tham Shi Yuan 4S128 Lim Yuan Wei 4S308. Contents. Brief introduction on rationale of project Brief literature review Objectives and hypotheses Independent, dependent and controlled variables Materials and methodology Data analysis
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Hormesis in Yeast Cao Tian Qin 4S104 Tham Shi Yuan 4S128 Lim Yuan Wei 4S308
Contents • Brief introduction on rationale of project • Brief literature review • Objectives and hypotheses • Independent, dependent and controlled variables • Materials and methodology • Data analysis • Application of project • References
Introduction • Uses of the yeast, Saccharomycescerevisiae
Introduction - Hormesis • 1888 - German pharmacologist Hugo Schulz observed that the growth of yeast could be stimulated by small doses of poisons • Poisons are actually stressor agents
Introduction - Hormesis • Certain stressor agents have been known to stimulate at low doses but inhibit at high doses e.g. antibiotics, aspirin, radiation • Principle of hormesis is not well-studied in yeast
Variables Materials and apparatus Methodology Experimental Procedure
Data Analysis Statistical analysis • t-test was conducted to test if difference in mean number of colonies was significant • p < 0.05 – significant • p > 0.05 – insignificant
Results Data Analysis Experimental Results
Effect of high concentration of Paracetamol on growth of yeast
Effect of high concentration of TCM on growth of yeast • At a high amount (300 mg) of Paracetamol and TCM, there was inhibition of yeast growth. • Both are identified as stressor agents.
0 mg (Control) 0 mg (Control) Hormetic effect of Paracetamol on growth of yeast 3 mg Paracetamol Yeast growth was stimulated at 3, 15 and 30 mg Paracetamoladded. 15 mg Paracetamol 30 mg Paracetamol
Data Analysis • Hormetic effect of Paracetamol on growth of yeast
0 mg (Control) Hormetic effect of TCM on growth of yeast 3 mg TCM TCM (Angelica sinensis)stimulated growth of yeast at 3, 15 and 30 mg added. 15 mg TCM 30 mg TCM
Data Analysis • Hormetic effect of TCM on growth of yeast
3 mg 0 mg (Control) 15 mg 30 mg 60 mg Hormetic effect of mixture of Paracetamol and TCM on growth of yeast The mixture of Paracetamol and TCM stimulated growth of yeast at all concentrations tested.
Hormetic effect of mixture of Paracetamol and TCM on growth of yeast
Data Analysis • Hormetic effect of mixture on growth of yeast
Conclusion Limitations Further Study Applications Discussion
Limitations • Side effects to yeast cells cannot be observed solely based on growth of yeast cells • Only growth rate is studied; other effects are unknown • e.g. Expression of certain genes in response to stressor agents applied
Further Study • Exposure of yeast to other stressor agents • e.g. UV radiation, antibiotics • Determine effect of stressor agents on level of protein synthesis in yeast
Applications • Increasing the efficiency of large scale growth of yeast starter cultures in industries • Higher biomass of yeast results in higher yields of products formed, e.g. ethanol.
References • Balzan, R., Sapienza, K., Galea, D.R., Vassallo, N., Frey, H. & Bannister, W.H. (2004). Aspirin commits yeast cells to apoptosis depending on carbon source. Microbiology, 150, 109-115. • Calabrese, E.J. (2004). Hormesis: a revolution in toxicology, risk assessment and medicine. EMBO Reports, 5, S37 – S40. • Calabrese, E.J. & Baldwin, L.A (2002). Defining hormesis. Human and Experimental Toxicology, 21, 91-97. • Hadley, C. (2003). What doesn’t kill you makes you stronger. EMBO Reports, 4, 924-926. • Tan, B.K.H. & Vanitha, J. (2004). Immunomodulatory and antimicrobial effects of some traditional Chinese medicinal herbs: a review. Current Medicinal Chemistry, 11, 1423-1430. • http://en.wikipedia.org/wiki/Hormesis